This is key, fellas:
and this:

1) Check your oil level. Is it high? Is it foamy?

2) Check for blowby.

I think you'll find one or the other.

Weather or not he changed the oil often enough, or used synthetic, or not - he rebuilt his engine. Maybe for the first time. We have to give him credit for doing that.

- Patrick

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1982 240D. 198k, Marine Blue/Blue, 4 Speed, Crank Windows, No Sunroof, No Rust, No Oil Leaks
2001 TDI. 197k, Lagoon Blue/Black, 5 speed, Chip, G60/VR6

maybe it's that negative pressure thing going on that another member had a while back? due to a restricted crankcase breather?

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1984 300D Turbo - 231k....totalled 11/30/07 RIP

Your thread is a little old now. Just thought I would express an opinion. Since you are able to discern the base oil burning is heavier at sometimes than others it seems that piston, piston rings, valve guides etc. are not involved to any signifigant degree. I would first try to establish if blowby pressure is within normal limits. If blowby is really excessive though you have found your problem. On the newer engines if blowby starts to get into the dangerous area it shuts the pump down. Some people have thought this feature was accidental perhaps but I have thought it intentional design. If not examine any point base oil could be getting into the cylinders very carefully. Never owned one of these earlier blocks myself but mention is made of a diaphram on the injection pump. Suspect the guys mean if it is cracked base oil will be going to where it should not. Basically if blowby is not excessive again I cannot see the basic block being the causitive agent if problem is not constant. I tend to believe you are getting surges of base oil as at a burn rate of 200 miles per quart the engine would not be thought to be fuelling itself on a constant basis with the base oil. Just a few of my thoughts probably worthless.

"Do a search on :
Pneumatic governor diaphram. You may have to search back several years."
---Palangi (Paul )
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"That doesn't seem to be the problem on my car.
I don't see the connection between the diaphram and sucking air (or burning oil!) anyhow."

"But why did it start burning oil suddenly? "----dieselBenz
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"mention is made of a diaphram on the injection pump. "---Barry123400
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Paul has owned these old blocks.... but dieselBenz dismissed that suggestion...

The vacuum pump on these models had a rubber diaphram. When it gets a hole in it, the vacuum produced sucks engine oil through, and it vents into the intake. Having the car pointed down at the front makes this worse, as the oil from the valve train runs down the front side of the chain case then. You can suck all the oil out of the engine and sieze it up if you don't watch it.

Easy fix, just remember to use the locktite on the center screw, or it will come out and pucture the diaphram again.

The air in the fuel is a leaking suction line. Cut it off and replace with a new hose. The old one is crimped on, I think, to a screw fitting. Common problem, and if not fixed will prevent starting eventually.

BTDT on both items.

Later vac pumps vent back into the crank case, and by 1980 or so were piston type rather than diaphram, so those models won't pull oil like that.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!

Ditto psfred on the vacuum pump. Also check that the engine is breathing properly - may have inadvertently forgot something on the rebuild.

Did you remember those copper washers on the fuel line fittings when you put everything back together? I clean them up with emory cloth - gets the ridges off. Common source of air leaks, in addition to the rubber-to-fitting connection.

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daBenz - 1970 220D

it sounds as there is definately a problem other than faulty rebuild. there could be mistakes made in the rebuild that contributed, but this is not a common problem, i dont think. i am clueless but hoping someone with experience will pick up and help out.

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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.

When you say "rebuilt"

What exactly was done to the motor- just to eliminate assumptions.


Michael

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Michael McGuire
83 300d
01 vw A4 TDI
66 Chevy Corsa
68 GMC V6 w/oD
86 300E

I tried to get info on that earlier...

"What exactly did you do in the rebuild ? Did you set the bore to piston specs differently for number one piston ?"

Had a look today at my 77 300d. it has a semi transparent hose from the vaccum pump to top of the breather. Since the normal travel of air is to the breather that hose should be completely oil free unless your diaphram has failed to some extent. If any oil present in that hose you have your problem. If not sure just disconnect it and see if your car runs normally. Cannot get any easier.